Apricot XEN Pentium 60, Руководство пользователя

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XEN OWNER'S HANDBOOK A/11
Inside the Apricot XEN
Appendix A
Note
The top location of this first Mbyte is 1M-1 or FFFFFh. This is because
in the first Mbyte there are 1M locations, starting at 0. Location 1M
is the start of the second Mbyte of address space.
The memory map above shows the uses of the first Mbyte of
address space. The memory map is arranged in this way in
order to be compatible with the ISA standard.
The region from 0 to 640k-1 (00000h to 9FFFFh) is used by
DOS. The operating system is loaded at the bottom of this area
and it uses the remainder to load applications and data.
Motherboard video adapter memory is accessed between 640k
and 768k-1 (A0000h to BFFFFh). In the XEN the motherboard
video BIOS is addressed between 768k and 800k-1 (C0000h to
C7FFFh).
Note
This region is often used by video BIOS on expansion cards. If an
expansion card with video BIOS is installed in a XEN the motherboard
video adapter must be disabled by removing jumper JP14.
The region from 800k to 896k-1 (C8000h to DFFFFh) is available
for expansion card ROM, other than video BIOS. The region
from 896k to 960k-1 (E0000h to EFFFFh) is reserved. While
address space from 960k to 1M-1 (F0000h to FFFFFh) is used
by the motherboard BIOS.
When installing expansion cards the area of most interest is
between 768k and 896k-1 (C0000h to DFFFFh).
Configuring expansion ROM
Expansion card ROM is addressed in the C0000h to DFFFFh
region of processor address space.